Posology
Oral administration
As food impairs the bioavailability of atenolol, it should not be taken with the food.
The dose must always be adjusted to individual requirements of the patients, with the lowest possible starting dosage. The following are guidelines:
Adults
Hypertension
A starting dose of 25 mg is recommended. The usual maintenance dosage in hypertension is 50-100 mg daily. The maximum effect will be reached after 1-2 weeks. If further improvement of the blood pressure is desired, atenolol may be combined with another anti-hypertensive e.g., a diuretic.
Angina
50-100 mg daily, depending on the clinical effect, in order to obtain a heartbeat in rest of 55-60 beats per minute. Increasing the dose above 100 mg daily does not generally lead to an increased antianginous effect. If desired the dosage of 100 mg daily can be divided in two dosages.
Cardiac arrhythmias
Initially controlled intravenously. A suitable oral maintenance dosage is 50-100 mg daily, given as a single dose.
Myocardial infarction
Initially controlled intravenously, followed by 50 mg orally about 10 minutes after the intravenous dose provided no adverse effects occur. This should be followed by a further 50 mg orally 12 hours later. Maintenance dose 100 mg daily in 1-2 dosages for 6 days or until discharge from hospital”.
Elderly
Dosage requirements may be reduced, especially in patients with impaired renal function.
Children
There is no paediatric experience with Atenolol and for this reason it is not recommended for use in children.
Renal failure
Since Atenolol is excreted via the kidneys, the dosage should be adjusted in cases of severe impairment of renal function.
No significant accumulation of Atenolol occurs in patients who have a creatinine clearance greater than 35 ml/min/1.73 m2 (normal range is 100–150 ml/min/1.73 m2).
For patients with a creatinine clearance of 15–35 ml/min/1.73 m2 (equivalent to serum creatinine of 300–600 micromol/litre), the oral dose should be 50 mg (two 5ml spoonfuls) daily and the intravenous dose should be 10 mg once every two days.
For patients with a creatinine clearance of less than 15 ml/min/1.73 m2 (equivalent to serum creatinine of greater than 600 micromol/litre), the oral dose should be 25 mg (one 5ml spoonfuls) daily or 50 mg (two 5ml spoonfuls) on alternate days and the intravenous dose should be 10 mg once every four days.
Patients on haemodialysis should be given 50 mg (two 5ml spoonfuls) orally after each dialysis; this should be done under hospital supervision as marked falls in blood pressure can occur.